Refrigerator



Oct. 30, 1934. L. A. cowAN, JR

REFRIGERATOR Filed Aug. 15, 1932 2 Sheets-Sheet 1 ZSnventor 5% M attorneys Oct. 30, 1934.- COWAN, JR

REFR I GERAT OR Filed Aug. 13, 1932 2 Sheets-Sheet 2 mm @m k (Ittomegs MMW Patented Oct. 30, 1934 UNITED STATES PATENT OFFICE REFRIGERATOR Lucian A. Cowan, Jr., Mobile, Ala.

Application August 13, 1932, SerialNo. 628,730

2 Claims. (01. 6295) The present invention relates to mechanical In the drawings the refrigerator 11 is of the refrigerators, and more particularly to means for conventional type provided with shelves 12 and insulating the cooling unit and its freezing coma door or doors 13. Disposed within the refrigpartment to lessen precipitation of moisture and erator, preferably in an upper corner thereof, is

5 prevent subsequent formation of frost due to cona cooling unit 14, which, in Figs. 1, 2 and 3, com- 6 tinued freezing of moisture on the exposed surprises three spaced parallel walls. Theevapoface of the unit. rator, which is preferably of the flooded type, but

One of the disadvantages of freezing units dismay be of any of the well known systems, and posed in refrigerators to act as a cooling medium communicates in the usual manner with a com- 10 is that food in the refrigerator is subject to desic pressor or other means (not shown) supplying 65 cation or loss of moisture. The moisture is exrefrigerant to the cooling unit, is formed by the tracted from the air in the refrigerator as it inner walls 15, 16 and drum 17 at the top therecomes in contact with the sub-freezing surfaces of. Within the freezing compartment formed by forming frost or ice on the unit, thus causing the the evaporator are shelves 18 suitably secured to air to become relatively dry and to absorb moisthe wall to support removable ice-trays 19. Sur- 70 ture from the contents of the refrigerator. This rounding the evaporator and spaced therefrom is usually referred to as dry cold, as distinis an outer wall 21. The space between walls 16 guished from wet cold, such as results from the and 21 is filled with an insulator or other subuse of melting ice for cooling refrigerated food stance 22 having limited heat conducting propercompartments. ties so as to act, to a greater or less degree, as '15 Another disadvantage in refrigerators of the an insulating wall between the evaporator and type wherein sub-freezing surfaces are exposed the food storage space 23 of the refrigerator. In to the air within the refrigerator is that formathe present instance, it has been found that tion of ice or frost on the unit lowers the efliparaffin is suitable for the desired purpose, but

25 ciency of the cooling unit and requires frequent other liquids, solids, or semi-solids may be uti- 80 defrosting. lized. Walls 15, 16 and 21 are formed from a This invention aims to obviate these disadmetal of high thermal conductivity, to facilitate vantages, first, by insulating the coils or tank heat exchange. As shown in the drawings, metal containing the refrigerant from the food comfins 24 are secured to wall 21 to provide for conpartment to a limited degree so that the surfaces duction of heat from the food storage space to 5 exposed to the air within the refrigerator are the cooling unit. maintained above freezing temperatures during The evaporator is closed on all sides except the a substantial portion of one entire cycle of opfront, an insulator door 25 being provided to pereration of the refrigerating apparatus and secmit access to the ice-trays. To obviate sticking ond, by insulating the freezing compartments of door 25, insulating plates 26, 2'7 are attached 90 from the air wit n the rator by means of to the cooling units, these plates preferably bea front of insulating material provided with suiting formed from a suitable insulating material ab e Openings and insulating doors P ates such as hard rubber, phenol condensate, or other form a Sub a y air-tight c e for the similar compositions. Interposed between plate 40 fr compartment op g 27 and wall 21 is a gasket 28 of cork or other suit- 95 the drawings'there fi luustramd two able flexible material. Door 25 bears against the bodiments of the invent on from which a clear Openings in the plates to provide an uptight undfirstaPdmg thereof Wm closure for the freezing compartment and, since 1 1s fl pfarspectlve or tefflgemtoz plate 26 is sufficiently removed from the evapl coolmg umt dlsposed t orator to remain above freezing temperatures,

Fig. 2 1s a front elevation, partly in section, of t d bse uent freezin around the door one type of cooling unit employed in the present mols i i 9 q g edges is inhibited. refrigerator, h d u 15 I Fig. 3 is a sectional view taken on the center As be Seen m t e g 0 line of Fig. 2; the evaporator, forming the freez ng compart- 05 Fig 4 is a front elevation f another for of ment, is maintained at sub-freezing temperacooling unit, shown partly in section, and inditures, whereas wall 21 is separated from the eating its position in the refrigerator; evaporator by a predetermined thickness of in- Fig. 5 is a sectional view taken on the center sulating filler 22. Obviously, the temperature line of Fig. 4. of the food storage compartment is higher than no that of the freezing chamber, and in practice I the insulation interposed between the walls is r such that wall 21 is maintained substantially at all times above 32 F. The spacing of the walls 12 and 21 is governed by the particular insulation employed, this being determined by known characteristics and experiments. The insulation may be introduced by any expedient method, but, in the present instance, a filling opening 29 is provided through which the substance is poured while in a fluid state.

In the form of the invention illustrated in Figs. 4 and 5, the refrigerator, only a portion of which is shown, is indicated at 11, the cooling unit 14' being suitably supported in an upper corner thereof. The cooling unit comprises a plurality of freezing coils 31 and an auxiliary coil 32, the former being arranged to accommodate removable ice-trays 19', while coil 32 surrounds a chamber 33 having therein a large removable tray 19" in which articles may be placed to be chilled, or which may be employed as a cold storage space.

Coils 31 and 32 are connected andare disposed in a box-like container having outer walls 21' and inner walls 34 and 35, all of the walls being formed from a metal of high thermal conductivity, and the inner walls conforming substantially to the curvature of coils 31 and 32, respectively, to form recessed chambers for the ice trays and chilling tray. The coils communicate in the usual manner with a compressor (not shown), through inlet 36 and outlet 37. Coils 31 bear directly against walls 34, but coil 32 is spaced from wall 35. The space between the inner and outer walls of the cooling unit housing or container is filled with a substance 22 having limited heat conducting properties.

As will be seen from the drawings, the walls of the ice tray compartments, being in direct contact with coils 31, are maintained at a relatively low temperature, whereas-walls 32 and 35 are separated from the coils by a predetermined thickness of the insulating filler. The temperature of chamber 33 is higher than that of the ice tray compartments and the temperature of the food compartment is still higher. In practice, the insulation interposed between the walls and coils is such that compartment 33 is maintained at or about freezing temperature while the walls 21 have a temperature of approximately 32 F. The ice-cube compartments are, of course, maintained at sub-freezing temperatures, due to their surfaces being in contact with coils 31 carrying the refrigerant.

In order better to conduct heat from food compartment 23' to the cooling unit, metal fins 24 are secured to walls 21. Also welded or otherwise fastened to walls 21', interiorly thereof, are angular plates 38 disposed to provide for more uniform transfer of heat from the walls to coils 31 and 32. These plates are perforated so that the insulating material will fill the spaces between the plates and the walls, thus preventing formation of dead air spaces in the unit.

Attached to the exterior surface of cooling unit housing 21 is aplate 26 similar to that described with respect to Figs. 1, 2 and 3. This plate isprovided with openings corresponding with those of the freezing compartments and the storage compartment, and the plate is extended to the periphery of the cooling unit. Interposed between the front plate 26' and the cooling unit is a smaller plate 2'7 of similar material extending to theperiphery of the compartment openings.

Also interposed between the front plate and the cooling unit is a gasket 28" of cork or suitable material. Plates 26', 27' and gasket 28' are each provided with openings corresponding with those in the cooling'unit to permit passage of trays 19' and 34.

The ice-trays shown in Figs. 4 and 5 are provided with front flanges 39 which bear against plate 26', providing a substantially air-tight closure for the" openings leading to the interior compartments in the cooling unit. The flanges are of sufficient insulating value to prevent frost from forming on their surfaces; and plate 26 is sufficiently removed by insulation from the coils 31 that they never reach a temperature below freezing. It will be seen, therefore, that the contacting surface between the flanges and the front plate is not subject to the formation of ice or frost, and hence no sticking results.

In lieu of flanges 39 formed on or secured to the ice-trays, each freezing compartment may be provided with an individual insulating door hinged to the cooling unit, and permitting insertion or withdrawal of the trays.

In refrigerators provided with a separate exterior door for access to the freezing compartments, a flange or dished plate 41 is connected to the front plate, this flange or plate being in contact with the refrigerator around the periphery of the opening in the refrigerator leading to the freezing compartments and extending to, and making contact with, the periphery of plate 26 attached to the cooling unit.

It will be seen that not only are air and odors from storage compartment 23 prevented from reaching the ice-tray compartments, but, when opening 42 is in communication with the exterior of the refrigerator, as when the door thereof is opened, outside air cannot reach the food compartment.

From the foregoing description it will be obvious that the cooling unit with its insulation interposed between the interior freezing compartments and its exterior cooling surface entirely eliminates formation of frost or ice on the exterior cooling surface. Due to the insulated front attached to the exterior of the cooling unit, and the insulating flanges or doors which form a substantially air-tight closure for these compartments, formation of frost in the interior freezing compartments is greatly reduced, due to the fact that air cannot circulate in these compartments, thus reducing the necessity of frequent defrosting; nor can odors from within the refrigerator permeate the freezing compartments.

While the invention has been described in detail, it is not to be construed as being limited to the illustrated forms, or to the insulating materials specifled.

What is claimed is:

1. In a refrigerator, the combination of a thermally insulated cabinet enclosing a food chamber and having a thermally insulated access door leading to said chamber; an evaporator mounted 140.

thermal conductivity of said housing being such that its exterior will be maintained by the evapaperture.

2. The combination defined in claim 1, in which the access door to said housing is mounted in:

aperture in said cabinet, the walls of the housing being connected with the margins of said LUCIAN A. COWAN, JR. 

